Refrigerating system defrosted by hot liquid refrigerants



J. B. COCANOUR 2,452,102 REFRIGERATING SYSTEM DEFROSTED BY HOT LIQUID REFHIGERANTS Filed Nov. 6, 1944 I N V EN TOR. JOHN A. mam aye Patented Oct. 26, 1948 REFRIGERATING SYSTEM DEFROSTED BY HOT LIQUID REFRIGERAN TS John B. Cocanour, San Jose, Calif., assignor to Colvin-Templeton, Inc., Oakland, Calif., a corporation of California Application November 6, 1944, Serial No. 562,189

29 Claims.

the heat stored in the refrigerant by the pgm reslsor for car%gng gpt t tre dggfig s ti n rgge g. is ur or proposed to utilize he refrigerant of the cooling system for effecting the de-frosting process by sending the refrigerant through .the coils of the evaporator and in ange. relation with the dr' MQheated condition when de-frosting is called for, whereby the defrosting process is carried out expeditiously, in a very short time, and with a minimum heating effect on the room to be cooled.

And finally, it is proposed to provide suitable means for carrying off the water of the de-frosting process in heat exchange mm the heated refrigerant to prevent re-freezlng of the water before it leavie'st'li'"fi56rii"f6'bi?o'bled.

*Furthr objects and advantages of my invention will appear as the specification proceeds, and the new and useful features of my cooling system will be fully set forth in the claims hereto appended.

The preferred form of my invention is illustrated in the accompanying drawing, the one figure of which diagrammatically explains the invention.

While I have shown only the preferred form of the invention, I wish to have it understood that Various changes or modifications may be made within the scope of the claims hereto attached without departing from the spirit of the invention.

Referring to the drawing in detail, my invention is intended to be used in connection with conventional refrigerating apparatus comprising a compressor I, a condenser 2, a receiver 3, a thermostatic expansion valve 4, an evaporator 5 and a conduit 6 connecting the above elements in series to make a complete refrigerating circuit.

The evaporator 5 is preferably of the conventional square box type adapted to be suspended from the ceiling of the room to be cooled and comprises a square frame 1 open at the bottom and at the four sides, with evaporator coils 8 mounted in the open sides and a fan 9 driven by the motor 9 disposed in the bottom to drive the air over the evaporator coils in forced circulation.

The evaporator is equipped with a drip pan l0 and may be provided, for the more effective operation of my invention, with hinged shutters ll along the sides thereof, the shutters being normally opened by the draft of the fan, but dropping into box closing position when the fan stops.

The compressor unit, including the compressor, the condenser and the receiving tank are mounted outside the room to be cooled, while the expansion valve usually is mounted as part of the evaporator, which latter is frequently referred to as the cooling unit.

The condenser, for more effective operation, is usually provided with a fan l2 driven by a motor l3.

The circuit thus far described is conventional. In operation, the compressor compresses vaporized refrigerant received from the evaporator, thereby heating the same, and delivers the refrigerant .to the condenser, where it is condensed to liquid form and delivered to the receiving tank. From the latter it is forced through the expansion valve to the evaporator, to be finally returned .to the compressor.

As the refrigerant passes through the evaporator, it absorbs heat units, thereby cooling the evaporator to a degree below the freezing point of water and the cold air is distributed through the room by forced draft.

As this operation continues, moisture from the room settles upon the evaporator and gradually freezes so as to cover the evaporator coils and .the drip pan with a layer of frost or ice. As this layer of frost increases in thickness, it retards forced circulation past the coils and also serves as an insulating medium reducing heat exchange between .the evaporator coils and the air forced past the same.

In time the layer of frost becomes so thick as to seriously interfere with the effective operation of the refrigerating apparatus, while the temperature of the refrigerant in the evaporator drops bg g ljmledgegree, due to the lack of proper heat exchange.

It then becomes necessary to de-frost or de-ice the evaporator. Various methods have been suggested and used for effecting periodic de-frosting, but as far as I am aware, the known methods either involve manual operation, relying upon the judgment and watchfulness of an operator .for starting the de-frosting process at the proper time, or periodic operation efiecting defrosting at certain intervals regardless of whether the defrosting is premature or overdue.

I fiso find that in present methods the defrosting process is carried on over an extended length of time which interferes with proper refrigeration and has a tendency to raise the temperature throughout the room in which the cooling unit is disposed.

In the present invention it is proposed to provide means whereby the drop in temperature in the evaporator below a predetermined degree initiates the de-frosting process and whereby the de-frosting process is stopped automatically immediately after the ice has disappeared.

It is further proposed to utilize the refrigerant itself for the de-frosting operation, and to provide means whereby the refrigerant can be sent through the evaporator either at a low temperature for the general refrigerating process, or at a high temperature for the de-frosting process. This allows the de-frosting to be accomplished in a very short period of time and leaves the remainder of the room substantially unaffected in temperature.

In carrying out my invention, I provide a water tank I5 between the compressor I and the condenser 2, the walls of the tank being suitably insulated.

Inside of the tank I provide a coil 6, connected into the general conduit 6, so that the refrigerant which leaves the compressor at a high temperature, passes through the coil and heats the water in the tank.

I further furnish a by-pass H, which branches off from the main cond'iiitfitween the receiving tank 3 and the expansion valve 4, connects with a heating coil I8 in the tank l5, thence leads toward the evaporator, taking a few turns 25 in the drip pan, and finally joining the main conduit on the opposite side of the expansion valve 4, as at 26.

This by-pass is provided, near the point where it branches oil, with a control valve 20, which is preferably of the solenoid type, adapted for electrio operation. A suitable pressure-responsive or temperature-responsive control switch 2| is provided at the evaporator to operate the control valve 20.

The switch might be set to open the valve at 5 Fahrenheit, and to close it at 34 Fahrenheit. s The same switch might be utilized to open the fan motor circuit when it opens the control valve, and to close the circuit when it closes the control valve.

A simple and conventional wiring diagram is shown to illustrate one preferred way in which the switch 2|, the valve 20 and the fan motors 9 and I3 may be connected into an electrical circuit. The main line wires are indicated at 30-3 Current normally flows from the main wire 30 through wire 32 to motor l3, thence through wire 33, switch 34 and. wire 35 back to th main wire 3|, the switch 34 being normally closed.

Current also flows from the main wire 30 to the motor 9', thence through wire 38, switch 31 and wire 35 to the main line 3|, the switch 31 being normally closed.

Thus, in the normal operation of the machine, the valve 20 is closed and the two switches 34-31 are closed to allow the motors 9' and I 3 to operate. When switch 2| closes, the solenoid 38 opens valve 23 and the two relays 4|42 open the circuits of motors 9' and I3, thereby stopping the fans. When switch 2| opens again, valve 20 closes and 4 the two switches 34-31 close again to allow normal operation to be resumed.

During the de-frosting period, water is liberated which drops on the drip pan and is drained off through pipe 22 which is preferably arranged in heat exchange relation with the refrigerant pipe I1 so as to keep from freezing until it leaves the room, a wall of which is indicated at 23.

In operation, my invention works as follows:

Normally the refrigerant takes its usual course, except that it passes through the coils l6 for heating the water in tank I 5,

When a layer of frost develops in the evaporator sufficiently thick to call for tie-frosting, the temperature within the evaporator drops to the predetermined degree necessary to close the switch 2| (which may be set to respond to temperature or pressure, since the pressure drops with the temperature), and this opens the control valve 20.

The opening of the valve is followed immediately by the closing of the expansion valve 4, and all the refrigerant then passes through the by-pass, absorbing heat in the tank is and reaching the evaporator in heated condition. Running over the drip pan and through the coils of the evaporator, the warm refrigerant will melt the ice in a few minutes.

Duringthis periog the fan motor is shut off so that there is no forced c re a on e wh1e E'EQEliElQEQR swnyailetssiirom theroonrhfthe closing thT'sl fyjters ll.

H ke-temperature about the cooling unit cannot rise above 32 F. until all the ice is melted, but will rise immediately thereafter. Thus, if the control switch is set to open at a temperature slightly above 32 F., say at 34 F., it is apparent that the de-frosting will be fully completed before valve 20 is closed, and on the other hand, that valve 20 will close after the de-frosting is completed.'

After valve 20 closes, the system will resume its normal operation. The water resulting from the de-frosting process will be drained off through pipe 22 and will remain in heat-exchange relation with the by-pass, until the water is outside of the room.

I claim: I y

1. A cooling system comprisin a conduit, a compressor, a condenser, a receiver, an expansion valve and an evaporator connected into the conduit in series for passing a refrigerant therethrough, a by-pass for the expansion valve having means for heating the refrigerant therein, and control means for thumwhereby the latter is opened KW a predetermined dro m em rature m the porator for defrost; ng the latter. .WMW

2. A cooling system comprising a conduit, a compressor, a condenser, a receiver, an expansion valve and an evaporator connected into the conduit in series for passing a refrigerant therethrough, a by-pass for the expansion valve having means for heating the refrigerant therein, and

of the de-frosting process in heat exchange relation with the by-pass to prevent the re-freezing of the water.

3. A cooling system comprising a conduit, a compressor, a condenser, a receiver, an expansion valve and an evaporator connected into the conduit in series for passing a refrigerant therethrougl a by-pass for the expansion valve having a section arranged in heat exchange relation with the conduit emerging from the compressor for heating the refrigerant in the by-pass, and control means for the by-pass whereby the latter is opened in response to a predetermined drop in 4. A cooling system comprising a conduit, a compressor, a condenser, a receiver, an expansion valve and an evaporator connected into the conduit in series for passing a refrigerant there through, a by-pass for the expansion valve having a section arranged in heat exchange relation with the conduit emerging from the compressor for heating the refrigerant in the by-pass, and control means for the by-pass whereby the latter is opened in esons p, ermined drop in term rature n the eva orator for derg s ng latter, an means""i'5r'??:?i"fyiiigbfi the water of the de-frosting process in heat exchange relation with the by-pass to prevent re-freezing of the water.

5. A cooling system comprising a conduit. a compressor, a condenser, a receiver, an expansion valve and an evaporator connected into the conduit in series for passing a refrigerant therethrough, a tank for holding water, a coil in said tank connected into the conduit between the compressor and the condenser for heating the water in the tank, a by-pass for the expansion valve having a coil arranged in said tank for heating the refrigerant in the by-pass, and contgol means for the by-pas h'reby the latte is opened in W q g, u gd drop in temperature in the evaporator for de-frosting the latter.

6. A cooling system comprising a conduit, a compressor, a condenser, a receiver, an expansion valve and an evaporator connected into the conduit in series for passing a refrigerant therethrough, a tank for holding water, a coil in said tank connected into the conduit between the compressor and the condenser for heating the water in the tank, a by-pass for the expansion valve having a coil arranged in said tank for heating the refrigerant in the by-pass, and control means for the by-pass whereby the latter is opened in res determined drop in tmperature in th app atpr or end e if? means for carrying off the water of the de-frosting process in heat exchange relation with the by-pass to prevent re-freezing of the water.

'1. A cooling system comprising a conduit, a compressor, a condenser, a receiver, an expansion valve and an evaporator connected into the conduit for passing a refrigerant therethrough, a by-pass for the expansion valve having a section arranged in heat exchange relation with the conduit emerging from the compressor for heating the refrigerant in the by-pass, and control means for the by-pass whereby the latter may be opened for passing the refrigerant therethrough for defrosting the evaporator.

8. A cooling system comprising a conduit, a compressor, a condenser, a receiver, an expansion valve and an evaporator connected intothe conduit for passing a refrigerant therethrough, a by-pass for the expansion valve having a section arranged in heat exchange relation with the conduit emerging from the compressor, control means for the by-pass whereby the latter may be opened for passing the refrigerant therethrough for defrosting the evaporator, and means for carrying 011? the water of the de-frosting process in heat exchange relation with the by-pass to prevent re-freezing of the water.

9. A cooling system comprising a conduit, a compressor, a condenser, a receiver, an expansion valve and an evaporator connected into the conduit for passing a refrigerant therethrough, a tank for holding a liquid, a coil in said tank connected into the conduit between the compressor and the condenser for heating the liquid in the tank, a by-pass for the expansion valve having a means arranged in said tank for heating the refrigerant in the by-pass, and control means for the by-pass whereby the latter may be opened for passing the refrigerant therethrough for defrosting the evaporator.

10. A cooling system comprising a conduit, a compressor, a condenser, a receiver, an expansion valve and an evaporator connected into the conduit for passing a refrigerant therethrough, a tank for holding a liquid, a coil in said tank connected into the conduit between the compressor and the condenser for heating the liquid in the tank, a by-pass for the expansion valve having a means arranged in said tank for heating the refrigerant in the by-pass, control means for the by-pass whereby the latter may be opened for passing the refrigerant therethrough for de-frosting the evaporator, and means for carrying of! the water of the de-frosting process in heat exchange relation with the by-pass to prevent refreezing of the latter.

11. A cooling system comprising a refrigeration circuit including a compressor for pumping a refrigerant therethrough whereby the refrigerant is heated, a condenser connected to the compressor discharge for receiving the refrigerant therefrom, a heat absorbing body arranged in heat exchange relation with the circuit between the compressor discharge and the condenser for absorbing heat from the refrigerant during the refrigeration process, and means for passing a condensed refrigerant in heat exchange relation with said body.

12. A refrigeration apparatus, comprising a compressor, a coil, a condenser, an expansion device, an evaporator, means connecting said compressor, coil, condenser, expansion device and evaporator in series and forming therewith a normal closed circuit for the flow of refrigerant. a receptacle having a liquid therein submerging said coil for absorbing and storingthe heat of compression dissipated from the refrigerant pass-- ing through said coil, means cooperating with a portion of said normal circuit to form a secondary closed circuit through said compressor and said evaporator, a portion of the secondary circuit being disposed in heat exchange. relation with the receptacle so that the heat absorbed by said liquid is added to the refrigerant when it flows through said secondary circuit to accelerate defrosting of said evaporator.

13. A refrigeration apparatus, comprising a compressor, a coil, a condenser, an expansion device, an evaporator, means connecting said compressor. coil, condenser, expansion device and evaporator in series and forming therewith a normal closed circuit for the flow of refrigerant, a receptacle having a liquid therein submerging said coil for absorbing and storing the heat of compression dissipated from the refrigerant passing through said coil, means cooperating with a portion of said normal circuit to form a secondary closed circuit through said compressor and said evaporator, a portion of the secondary circuit being disposed in heat exchange relation with the receptacle so that the heat absorbed b said liquid is added to the refrigerant when it flows through saidfixcon'dary circuit to accelerate defrosting of said evaporator, and control means for the secondary circuit whereby the latter may be opened for passing the refrigerant therethrough for defrosting the evaporator.

14. A refrigeration apparatus, comprising a compressor, a coil, a condenser, an expansion device, an evaporator, means connecting said compressor, coil, condenser, expansion device and evaporator in series and forming therewith a normal closed circuit for the flow of refrigerant, a receptacle having a liquid therein submerging said coil for absorbing and storing the heat of compression dissipated from the refrigerant passing through said coil, means cooperating with a portion of said normal circuit to form a secondary closed circuit through said compressor and said evaporator, a portion of the secondary circuit being disposed in heat exchange relation with the receptacle so that the heat absorbed by said liquid is added to the refrigerant when it flows through said secondary circuit to accelerate defrosting of said evaporator, and COQQLQLWQMQ; the by=pa ss whereby the latter is opened in respons to a,predetermined drop in temperature in 'thffle v aporator for defrosting the latter.

15. fref'rigeration apparatus, comprising a compressor, a coil, a condenser, an expansion device, an evaporator, means connecting said compressor, coil, condenser, expansion device and evaporator in series and forming therewith a normal closed circuit for the flow of refrigerant, a receptacle having a liquid therein submerging said coil for absorbing and storing the heat of compression dissipated from the refrigerant passing through said coil, means cooperating with a portion of said normal circuit to form a secondary closed circuit through said compressor and said evaporator, a portion of the secondary circuit being disposed in heat exchange relation with the receptacle so that the heat absorbed by said liquid is added to the refrigerant when it flows through said secondary circuit to accelerate defrosting of said evaporator, control means for the secondary circuit whereby the latter may be opened for passing the refrigerant therethrough for defrosting the evaporator, and means for carrying off the water of the defrosting process in heat exchange relation with the secondary circuit to prevent the re-freezing of the latter.

16. A cooling system, comprising a refrigeration circuit including an evaporator, and a compressor for pumping a refrigerant through the circuit whereby the refrigerant is heated, a coil connected directly to the compressor discharge, a heat absorbing body arranged in heat exchange relation with the coil for absorbing and storing heat from the refrigerant during the refrigeration process, and a defrosting circuit including the same evaporator and the same compressor and having a section disposed in heat exchange relation with the said body to extract heat therefrom.

17. A cooling system, comprising a refrigeration circuit including an evaporator, and a compressor for pumping a refrigerant through the circuit whereby the refrigerant is heated, a coil connected directly to the compressor discharge, a heat absorbing body arranged in heat exchange relation with the coil for absorbing and storing heat from the refrigerant during the refrigeration process, a defrosting circuit including the same evaporator and the same compressor and having a. section disposed in heat exchange relation with the said body to extract heat therefrom, and control means for the defrosting circuit whereby the latter may be opened for passing th refrigerant therethrough for defrosting the evaporator.

18. A cooling system, comprising a refrigeration circuit including an evaporator, and a compressor for pumping a refrigerant through the circuit whereby the refrigerant is heated, a coil connected directly to the compressor discharge, a heat absorbing body arranged in heat exchange relation with the coil for absorbing and storing heat from the refrigerant during the refrigeration process, a defrosting circuit including the same evaporator and the same compressor and having a section disposed in heat exchange relation with the said body to extract heat therefrom, control means for the defrosting circuit whereby the latter may be opened for passing the refrigerant therethrough for defrosting the evaporator, and means for carrying off the water of the defrosting process in heat exchange relation with the defrosting circuit to prevent re-freezing of the latter.

19. A cooling system, comprising a refrigeration circuit including an evaporator, and a compressor for pumping a refrigerant through the circuit whereby the refrigerant is heated, a coil connected directly to the compressor discharge, a heat absorbing body arranged in heat exchange relation with the coil for absorbing and storing heat from the refrigerant during the refrigeration process, a defrosting circuit including the same evaporator and the same compressor and having a section disposed in heat exchange relation with the said body to extract heat therefrom, and control means for the defrosting circuit whereby the latter is opened in response to a predetermined drop in temperature in the evaporator for defrosting the latter.

20. A cooling system, comprising a refrigeration circuit including, a compressor for pumping a refrigerant therethrough whereby the refrigerant is heated, a condenser connected to the compressor discharge for receiving the refrigerant therefrom, a heat absorbing body arranged in heat exchange relation with the circuit between the compressor discharge and the condenser for absorbing and storing heat from the refrigerant during the refrigeration process, and a defrosting circuit including the same compressor and having a section disposed in heat exchange relation with the said body to extract heat therefrom.

21. A cooling system, comprising a refrigeration circuit including, a compressor for pumping a refrigerant therethrough whereby the refrigerant is heated, a condenser connected to the compressor discharge for receiving the refrigerant therefrom, a heat absorbing body arranged in heat exchange relation with the circuit between the compressor discharge and the condenser for absorbing and. storing heat from the refrigerant .luring the refrigeration process, a defrosting circuit including the same compressor and having a.

section disposed in heat exchange relation with the said body to extract heat therefrom, and control means for the defrosting circuit whereby the latter may be opened for passing the refrigerant therethrough.

22. A cooling system, comprising a. primary closed circuit including a compressor, a coil, a condenser, a receiver, an expansion device, an evaporator and a conduit connecting the compressor, coil, condenser, receiver, expansion device and evaporator in series for passing a refrigerant therethrough, and a secondary closed circuit including the compressor and the evaporator and a by-pass for the expansion device, a portion of the secondary circuit being disposed in heat exchange relation with the said coil.

23. A cooling system, comprising a primary closed circuit including a compressor, a coil, a condenser, a receiver, an expansion device, an evaporator and a conduit connecting the compressor, coil, condenser, receiver, expansion device and evaporator in series for passing a refrigerant therethrough, and a secondary closed circuit including the compressor and the evaporator and a by-pass for the expansion device, a portion of the secondary circuit being disposed in heat exchange relation with'the said coil, and control means for the by-pass whereby the latter may be opened for passing .the refrigerant therethrough for defrosting the evaporator.

24. A cooling system, comprising a primary closed circuit including a compressor, a coil, a condenser, a receiver, an expansion device, an evaporator and a conduit connecting the compressor, coil, condenser, receiver, expansion device and evaporator in series for passing a refrigerant therethough, and a secondary closed circuit including the compressor and the evaporator and a by-pass for the expansion device, a portion of the secondary circuit being disposed in heat exchange relation with the said coil, control means for the by-pass whereby the latter may be opened for passing the refrigerant therethrough for defrosting the evaporator, and means for carrying 011 the water of the defrosting process in heat exchange relation with the by-pass to prevent re-freezing of the water,

25. A cooling system, comprising a primary closed circuit including a compressor, a coil, a condenser, a receiver, an expansion device, an evaporator and a conduit connecting the compressor, coil, condenser, receiver, expansion device and evaporator in series for passing a, refrigerant therethrough, and a secondary closed circuit including the compressor and the evaporator and a by-pass for the expansion device,- a portion of the secondary circuit being disposed in heat exchange relation with the said coil, and control means for the by-pass whereby the latter is opened in response to a predetermined drop in temperature in the evaporator for defrosting the latter.

26, A cooling system, comprising a primary closed circuit including a compressor, a coil, a condenser, a receiver, an expansion device, an evaporator and a conduit connecting the compressor, coil, condenser, receiver, expansion device and evaporator in series for passing a refrigerant therethrough, a receptacle having a liq. uid therein submerging said coil for absorbing and storing the heat of compression dissipated from the refrigerant passing through said coil, a secondary closed circuit including the compressor and the evaporator and a by-pass for the expansion device, a portion of the secondary circuit being disposed in heat exchange relation with the receptacle to absorb heat from the liquid.

27. A cooling system, comprising a primary closed circuit including a compressor, a 0011, a condenser, a receiver, an expansion device, an evaporator and a conduit connecting the compressor, coil, condenser, receiver, expansion device and evaporator in series for passing a refrigerant therethrough, a receptacle having a liquid therein submerging said coil for absorbing and storing the heat of compression dissipated from the refrigerant passing through said coil, a secondary closed circuit including the compressor and the evaporator and a by-pass for the expansion device, a portion of the secondary circuit being disposed in heat exchange relation with the receptacle to absorb heat from the liquid, and control means for the by-pass whereby the latter may be opened for passing the refrigerant through the secondary circuit for defrosting the evaporator.

28. A cooling system, comprising a primary closed circuit including a compressor, a coil, a condenser, a receiver, an expansion device, an evaporator and a conduit connecting the compressor, coil, condenser, receiver, expansion device and evaporator in series for passing a refrigerant therethrough, a receptacle having a liquid therein submerging said coil for absorbing and storing the heat of compression dissipated from the refrigerant passing through said coil, a secondary closed circuit including the compressor and the evaporator and a by-pass for the expansion device, a portion of the secondary circuit being disposed in heat exchange relation with the receptacle to absorb heat from the liquid, control means for the by-pass whereby the latter may be opened for passing the refrigerant through the secondary circuit for defrosting the evaporator, and means for carrying ofi the water of the defrosting process in heat exchange relation with the by-pass to prevent the re-freezing of the water.

29. A cooling system, comprising a primary closed circuit including a compressor, a coil, a condenser, a receiver, an expansion device, an evaporator and a conduit connecting the compressor, coil, condenser, receiver, expansion device and evaporator in series for passing a refrigerant therethrough, a receptacle having a liquid therein submerging said coil for absorbing and storing the heat of compression dissipated from the refrigerant passing through said coil, a secondary closed circuit including the compressor and the evaporator and a by-pass for the expansion device, a portion of the secondary circuit being disposed in heat exchange relation with the receptacle to absorb heat from the liquid, and control means for the by-pass whereby the latter is opened in response to a predetermined drop in temperature in the evaporator for defrosting the latter.

JOHN B. COCANOUR.

. REFERENCES CITED The following references are of record in the file of this patent:

Certificate of Correction Patent No. 2,452,102. October 26, 1948.

JOHN B. COCANOUR It is hereby certified that errors appear in the above numbered patent requiring correction as follows:

In the grant, line 6, and in the heading to the printed specification, line 3, title of the invention, strike out the word LIQUID; column 1, lines 2 and 3, strike out refrigerating system defrosted by hot liquid refrigerant and insert instead cooling systems; a and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the casein the Patent Oflice.

Signed and sealed this 12th day of July, A. 1949.

[sEAL] THOMAS F. MURPHY,

Assistant 0' ommz'ssz'oner 0 f Patents. 

